Train signaling system



y 1938. H. w. RICHARDS 2,118,476

TRAIN SIGNALING SYSTEM Original Filed Oct. 19, 1951 Elma/WM:

792mm WCHARDS,

Patented May 24, 1938 I 2,118,476

UNITED STATES PATENT OFFICE 2,118,476 TRAIN SIGNALING SYSTEM Harry Richards, New York, N. Y; Substitute for application Serial No. 569,766",

October 19, 1931. This application March 16, 1937, Serial No. 131,217

12 Claims. (01. 246-63) This invention relates to an automatic system ber of radial projections of sufiicient length to for transferring electrical communications to vecause'the arm of an armature to be moved tohicles in motion and has for its object to provide ward or away from a fixed contact point to close a system which is simple in parts and more effior open the circuit thereof. That is to say, there cient in operation than those heretofore prois provided a wheel 20 having equally spaced proposed. This application is a refile of applicants jections 2! which, as the wheel rotates, succesprior application Serial No. 569,766 filed October: sively move the pivoted arm 22 away from the 19, 1931. fixed contact 23, said arm being normally held With these and other objects in view the inagainst said contact by virtue of current passing vention resides in the novel details of constructhrough an indication magnet 24 in the circuit of 10 tion and combinations of parts constituting the the signal desired to be transmitted. Thus it apparatus as well as in the novel steps and comwill be seen from the drawing that the arm 22 binations of steps constituting the method of will be held against the periphery of the wheel transmitting the communications, as will be disby the forces created by the electro-magnet 24;

closed more fully hereinafter and particularly that when the flats of said wheel are in contact 15 pointed out in the claims. with said arm the contact point 23 will be closed;

The accompanying drawing forming a part of and that the projections 2| successively move this specification is a diagrammatic representasaid arm in a direction away from said contact tion of a system by which the principles of this point to open the latter. Since the shaft it invention may be carried out. In said diagram of the motor will have a definite R. P. M. after it 20 are contained the trackside layout as well as the reaches its prescribed speed, the wheel 20 will layout carried by the vehicle in motion. cause a definite number of interruptions per see- In the drawing the trackside equipment con- 0nd, in any circuit controlled by the fixed consists of an inductor element comprising a lamitact 23 and the arm 22, in accordance with the nated structure I having thereon a plurality of number of projections 2| on said wheel. 25 cores 2, 3, 4 and 5, each core having thereabout The arm 22 is connected in circuit to the free a coil which may or may not be connected in end of the coil 6 which, as above stated, is serialseries with the coils of the adjacent cores. In the ly connected with the other coils I, 8 and 9. Since drawing these coils are indicated respectively by the arm l3 and the fixed contact 23 are eleco the numerals 6, 1, 8 and 9 and are shown contrically connected it will therefore be seen that nected in series. The free end of coil 9 is consaid coils are disposed in a closed circuit when nected to the armature of a relay ID which is 10- the contacts I I, I2 and 23 are closed. At low cated in the block next in advance of the block speeds of the motor the governor I! will cause in which I is located, said relay being enerthe contact I2 to open, and when this is the case gized through a standard track circuit as will be the circuit of said coils will be open regardless 35 readily understood, said relay becoming deof any condition of contact 23. The circuit of energized when a train enters the track section the coils will also be open whenever armature II to which said relay is connected. The contact is in open-circuiting position. However, with the point ll of said relay is connected to a fixed conmotor turning at the prescribed speed and the tact l2 which is adapted in turn to be contacted contact l2 closed, the circuit including said coils 0 by a movable spring tensioned arm l3 actuated will be successively opened and closed in accordby a governor operated sleeve M. In other words, ance with the actuation of the arm 22 by the a motor having an armature I5 and a field coil wheel 20. l5a, energized by current from any suitable Any number of other wheels such as 20 may s ur is pr v d d w t a s a r s t d by be rigidly mounted on the shaft it but, for 45 the dash line l6 upon which is mounted a typical purposes of illustration, only one other such wheel governor I! connected to the sleeve l4 slidable on has been indicated at 25, said wheel having a said shaft, said Sleeve being positioned to control plurality of equally spaced radial projections 26 the movement of the spring pressed arm I3 todifferent in number from the projections 2| for ward or away from the contact l2. The purpose the purpose of providing a different number of 5 of the governor is to leave the contact l2 open interruptions per second in the circuit including until the speed of the motor is up toa prescribed the inductor coils 6, I, 8 and 9. The wheel 25 rate. functions similarly to wheel 20. In other words,

Rigidly mounted on the shaft l6 are any num associated with the wheel 25 is a pivoted arm 21,

her of wheels each having a predetermined num a fixed contact 28 and an electro-magnet 29 55 similar to the parts 22, 23 and 24 above described, the electro-magnet 29 being in the circuit of a signal desired to be transmitted, which signal is different from the signal controlling the other magnet 24. It should be stated that the arms 22 and 27 are so constructedthat when their control magnets 24 and 29 are deenergized, said arms will, by the action of gravity, be moved away from any contact with the wheels or their projections, thus positively keeping open the contact points 23 and 28. Therefore, the purpose of the magnets 24 and 29 is to keep said arms in' contact with their controlling wheels.

It is to be observed that the coils 6, I, 8 and 9 are connected in series with the contacts 12 and 23, and that the contact 28 is located in a shunt circuit having parallel relation with the contact 23 so that the circuit including contact l2 will be completed through either of the contacts 23 or 28 according to the condition of the magnets 24 and 29.

On the vehicle, such as a locomotive, there is provided an inductor comprising a laminated structure indicated at 35 whose ends terminate in the pole pieces 35 and 31, the latter having mounted thereon a coil 38 constantly energized by alternating current from the generator 39, said coil thus becoming a primary coil. Also on the pole 31 is mounted a second coil 40 one end of which is connected as by the wire 4| to a primary coil 42 on the transformer generally indicated by the numeral 43, the other end of the primary 42 being connected as by the wire 44 to one end of a coil 45 disposed on the other pole 36 of the train carried inductor. The wire 46 connects the two free ends of the coils 49 and 45. Thus 40 and 45 become secondary coils connected in series but they are also connected in opposition due to the direction of their windings and their locations with respect to the primary coil 38.

' The coil 49 being on the same pole with the primary 38 and closely adjacent thereto is capable of having induced therein a current which is practically constant in voltage and regardless of a change in the flux produced by the primary 38. In this connection, it should be stated that the train inductor 35 is mounted so as to pass over the trackside inductor l and, when this occurs, any magnetic flux set up in the train inductor 35 by the primary coil 38 may complete its circuit through the trackside inductor as indicated by the heavy line 41, the train inductor moving in the direction of the arrow 48.

The coil 45 will have induced therein a voltage dependent upon the amount of flux passing through the pole 36. In other words, there will be a certain amount of magnetic flux passing through the train inductor when it is not over the trackside inductor l, and this amount of flux will be increased when the'two inductors are in registry, the trackside inductor forming a path of low reluctance for said flux. This condition, however, may be changed according to the condition of the trackside circuit including the coils 6, 1, 8 and 9.

In other words, if this circuit is open as through the contact I2 or 23, then the path of low reluctance will cause an increase in the magnetic flux and a corresponding increase in the amount of induced voltage in the coil 45. With the coils 6, I, 8 and 9 in a closed circuit, each coil will have the effect of choking the passage of the magnetic flux from the train inductor to and through the trackside inductor, thereby preventing an increase in the magnetic flux and preventing any change in the normal voltage of coil 45. The amount of current normally induced in coil 49 by the primary is greater than that induced in the coil 45, thus establishing a positive flow of current through the primary of the transformer 43. When, however, the amount of induced voltage in coil 45 is increased then, due to the fact that the coils 49 and 45 are connected in opposition, the one induced voltage will tend to neutralize the other, thereby in efiect producing no flow of current through the primary of said transformer.

From the foregoing, it will therefore be understood that the frequency of the pulsation in the circuit including the transformer primary coil 42 will vary in accordance with the number of interruptions per second created in the trackside circuits by the wheels 20, 25, etc. The train carried apparatus includes relays which are connected with the transformer and which are subject therefore to the variance in said frequency, each relay being designed to match the frequency initiated by a specific wheel. In other words, the transformer 43 carries a secondary coil 50in the circuit of which are connected in parallel a plurality of relays such as 5|, 52, 53, etc., the relay 5| operating on any frequency and the remaining relays 52, 53 etc., operating on predetermined frequencies which correspond respectively with the frequencies established by the wheels 25, 29 etc.

This is accomplished by the use of metallic reeds as armatures for certain of the relays, which reeds are adjusted to vibrate in accordance with the frequencies picked up by their associated magnets. In other words, the magnet 5| has a non-vibratory armature 54 whereas the magnets 52 and 53 have respectively the vibrator reeds 55 and 56 for their respective armatures, these vibratory reeds being rigidly supported at one end by any suitable bracket such as indicated by the numerals 51 and 58. Each bracket carries a clamping device designated at 59 and 50 which devices are adapted tobe adjustably moved on the brackets to change the vibratory length of the reeds.

The brackets 51 and 58 also carry single fixed contacts shown at 50 and BI respectively which contacts are insulated from their supporting brackets and are adapted to be repeatedly engaged through the vibration of their respective reeds 55 and 55, but when the frequency of the current passing through any one magnet is not of the same characteristic as the vibratory period of its associated reed, then that reed will remain natural period of vibration of its reed 56, then said reed will vibrate violently against the contact point 6| in accordance with the well known laws of resonance. This vibration is indicated in the diagram by the solid and dashed line positions of the reed 56, and such vibration will open and close repeatedly any circuit of which the contact 6| is a part. d

On the vehicle is a selector comprising an insulating medium 55 preferably mounted concentrically with respect to a shaft 65 constantly under an urge of rapid rotation, in the direction of the arrow, from any suitable source of power such as clockwork, a magnetic drag, or a friction drive, but which shaft may at times be stopped. This shaft has rigidly mounted thereon, and within said insulator, a disk member constituting a se lector 61 having a radially extending lug '68 adapted to contact, and be stopped by, pins extendible into the path of said lug. Also mounted rigidly on said shaft is another disk member 69 provided in its periphery with a plurality of spaced notches I9, each adapted to be engaged by a correspondingly shaped holding finger 86 constituting the free end of a pivoted-lever H serving as the armature of a holding magnet I2, said armature being under the tension of a spring I3 urging disengagement of said finger 86 with respect to a notch I0. I

- Mounted on the insulator'member 65 at spaced intervals are a plurality of binding posts I4, I5, I6 each extending through the insulator member and carrying a spring contact so disposed as to be wiped by the lug 68. The relative positions of the stop pins and the spring contacts, as well as the dimension of the lug, are such that, when held by a stop pin such as 11, said lug will be in engagement with one of the spring contacts. In other words the pin 11, passing through a magnet GM, is normally held out of the orbit of said lug by the spring I8 when said magnet is deenergized, but the outer end of the pin carries an armature I9 which is attracted by the magnet when the latter is energized. Since the force of said magnet is greater than the force of said spring, energization of said magnet causes movement of the pin 11 into the orbit of said lug.

In similar manner, there is provided a magnet YM whose pin- 89 likewise is of the nature of the core of a solenoid and which has the same spaced relation with the spring contact of binding post I5 that the pin 71 has with respect to the spring contact of the binding post 16. The magnet YM functions similarly to the magnet GM namely, when it is energized it causes pin 89 to move inwardly with respect to the insulator member 65 against the tension of the spring 8|, coming to rest in the orbit of the lug 68. A third magnet RM is provided which operates in a manner reverse to the operation of the magnets GM and YM. That is to say, when the magnet RM is energized it attracts the armature 82 carried at one end of the pin 83 thereby moving said pin out of the orbit of said lug. Asp ring 84, operating against a guide bracket 85 for said pin, moves said pin into said orbit when RM is deenergized.

Associated with the magnet GM is a fixed contact 99 and a movable contact member 9|, the latter under the urge of a spring 92 normally tending to-separate said contacts. The pin 11 of said magnet has an insulated end bearing against the movable contact 9|. It thus results that energization of magnet GM, causing movement of the pin 11 into the orbit of the lug 68, also permits the spring 92 to cause disengagement of the contacts 99 and 9|. Reversely, deenergization of said magnet permits the spring I8 to move pin 17 out of said orbit, and in this movement said pin causes a closing of the contact members 99 and 9|. In like manner the magnet YM has its pin 89 insulatedly bearing against the movable contact member 93 under tension of the spring 99 and adapted to open and close with its fixed companion contact member 95.

It has been found desirable to make the fixed contacts 99 and 95 somewhat yieldable so that they will be closed by their corresponding movable members 9| and 93 immediately prior to the ultimate release of the lug 68 by either of the stop pins II or 89. The reason for this is that it is intended that the circuit through the holding magnet I2 is to be completed prior to disengagement of any stop pin with the lug 68 so that said holding magnet, through the attraction of its armature, will cause the locking finger 86 to move into a notch I9 to hold the shaft 66 from rotating further, said finger thereby continuing the engagement of the lug 68 with a spring contact member. In this respect, it should here be stated. that the notches 19 are so spaced about the periphery of the holding disk 69 that, when the lug 68 is stopped by any pin such as II, there will be a notch I9 in position to be engaged by the holding finger 86.

The holding circuit comprises the magnet I2,

wire I99, contacts 90, 9|, wire |9|, contacts 95, 93, wire I92, contact I03, armature 54 of the magnet 5I, wire I94, battery I95, and wire I96 to the holding magnet I2.

" The GM magnet is operated by current from the battery I95 passing over the wire I9I to and through the vibrating reed 56 and itscontact 6|, wire I98 to and through the GM magnet, thence over the wire I99 to and through the RM magnet, thence over the wires 9 and I96 back to the battery. A condenser III is connected in shunt circuit between the wires I91 and I98 around the reed 56 and its contact 6|, to minimize the arcing at said contact.

The circuit controlling the YM magnet starts with the battery I95 from which the current passes over the wire 34 to the point II2, a portion of the current passing over the wire 3 to and through the vibrating reed 55 and its contact 69, thence over the wire IM to and through the YM magnet and over the wire 5 to the point H6 on the wire I99, the current returning to battery as above mentioned by way of the wire I99, magnet RM, and wires H9 and I06. A condenser III is connected in shunt circuit between the wires H3 and H4 around the reed 55 and its contact 69, to minimize the arcing at said contact.

It is to be particularly observed that the magnet RM is connected in the common return circuit of the magnets GM and YM so that when either of the magnets GM or YM is energized the magnet RM will be energized also. The reason for this connection is as follows. When the magnets are deenergize'd, the pin 83 of RM is normally projecting into the orbit of the selector lug 68 to stop it in position to close a circuit through the R lamp which is red, this being on the side of safety should the circuits through GM and YM become defective. Conversely, when RM is energized in conjunction with either GM or YM, the pin 83 of RM will be drawn out of the orbit of said lug, while the pin of either GM or YM (as the case may be) will be advanced into said orbit to stop said lug in engagement with a spring contact to close the circuit through the cablamp associated with GM or YM.

In other words, the binding post I4 associated with RM is connected as by the wire I29 with the R lamp (red) in the locomotive cab; the binding post I5 associated with YM is connected as by the wire |2I with the Y lamp (yellow) in the cab; and the binding post I6 associated with GM is connected as by the wire I22 with the G lamp (green) in said cab. All three lamps R, Y, and G have a common return in the wire I23 to the point I29 on the wire I96 back to battery I95. Current from said battery passes over the wires I94 and H3 to the point I25 and thence over the wire I26 to enliven the shaft 66 of the selector.

The current passes to the selector disk 7;;

filifrom said shaft and passes through the lug 58 thereof to the spring contact engaged by said lug and associated with one of the binding .posts suchas 16 to complete the circuit through and illuminate the lamp which is controlled by that particular binding post.

, From the foregoing, it will be understood that there may be any number of the magnets such as GM disposed in any arrangement about the insulator member 65; that for each of such magnets there will be a corresponding frequency relay such as 52; and that there also will be a corresponding indication controller such as the magnet 29. Also it will be understood that the frequency relays 5|, 52 and 53 and others will all be connected in parallel with the secondary coil 50. of the transformer 53. Further, while the diagram has shown the GM, YM and RM magnets as controlling respectively the G, Y and R lamps in the cab of the locomotive, it is to be understood that these magnets as well could control devices or mechanism other than lamps. Also, additional magnets could be placed about the selector insulator 65, each to control a mech. anism or device in addition to the lamps so controlled and illustrated.

vFor example, there could be an additional magnet on the selector member 65, which for this exempliflcation mightbe called BM, which would be similar in construction and operation to GM and which would be connected so as to control the actuation of brake mechanism whereby, under certain trafiic or emergency conditions, there would be an automatic application of the brakes. As another example, an addi tional magnet similar to GM in construction and operation could be utilized for the control of a visual, an audible, or a visual-audible warning device in the interest of public safety, thereby eliminating the vagaries and hazards of human attendance to such warnings.

In addition to the foregoing, it will also be understood that the lug 68 of the selector disk could be made of a dimension great enough to span a plurality of spring contact members, said plurality arranged either in series circumferen tially of the selector element, or arranged side by side in a diametric plane of said selector, as a result of which a combination of controls could be obtained, such for example as the simultaneous flashing of the Y and R lamps, the simultaneous flashing of the R lamp and application of the brakes, or the flashing of the Y lamp and the giving of a warning signal, etc. There could be, as well, a plurality of trackside and train carried inductors, each with associated equipment as herein illustrated, further resulting in additional combinations of control and signal possibilities.

rther, a plurality of selector disks could be mounted on the common shaft EEL'each disk having associated therewith a holding device, a set of cooperating magnets, contacts, etc., the same as the disk 67 and its cooperating holding device 69, 12, 86, magnets GM, YM, RM, and contacts associated with the binding posts I 3, l5, 16. Or a plurality of selector groups, each independent of the otherycould be employed to satisfy the needs of the service and system. While, in the diagram, the selector magnets GM, YM, etc., are shown to be controlled by frequency relays employing a tuned reed to operate an electrical contact, it is to be understood that any suitable form of electrical or mechanical devices may be used to indicate the presence of a predetermined frequency in the secondary coils of the train i'n'-' ductor.

From the foregoing, it will thus be seen and understood that, to light the green lamp in the engine cab to indicate a clear condition of track, the magnet 24 is energized thereby creating a tendency for the armature 22 to be pressed against the wheel 20 and its projections 2!, so that the rotation of said wheel will cause an opening and closing of the contact 23 in the circuit including the trackside coils. This interruption of the circuit through the contact 23" is of a frequency depending upon the R. P. M. of the motor shaft l6 and the number of projections 2| on the wheel 20. This interruption oithe trackside coil circuits causes a corresponding interruption in the path of low reluctance in the trackside inductor, thereby causing the voltage induced in the secondary 45 to pulsate with the corresponding frequency.

In other words, when the circuit through the trackside choke 0011s is open there will be an increase in the induction of voltage in the coil 45 so as to neutralize the voltage in the coil 40, but when said choke coils are in closed circuit, the magnetic fluxwill not be increased, so that the voltage including that of the transformer primary 42 will be of normal amount. The current in the secondary circuit of the train inductor is therefore made to fluctuate in its pulsation in accordance with the variance in interruption of the trackside circuit. Obviously, the transformer 43 causes a corresponding variance in pulsation in the secondary circuit thereof, and this variance is transmitted through the magnets 52, 53 etc. to that reed which is in synchronous resonance with said pulsation. The magnet 5-l is normally energized with current of the same frequency as supplied by the generator 39.

The purpose of the transformer 43 is to transform the voltage supplied by the secondary coils of the train inductor so that the relays may be operated on the most suitable voltage, regardless of the voltage necessary to operate the train inductor. In other words, the transformer 43 always has voltage therein in accordance with thedifference between the voltages of coils 40 and 45, which energizes the primary 42, and therefore the secondary 50 will receive a corresponding induced current to energize the magnets connected in circuit therewith.

The period of vibration of the reeds being adjusted through their clamps to operate on a frequency higher than the frequency supplied by the generator 39, each reed is not sufliciently affected by the normal generator frequency to open and close its contact. In this respect the magnets 52, 53 etc. are loosely coupled with respect to their reeds so that only that reed will be vibrated having a period of vibration corresponding with the frequency of the current passing through said magnets.

It thus results that the R. P. M. of the shaft IS in conjunction with the number of projections 2| on the wheel 20 Will produce such interruption in the frequencies of the trackside and train carried circuits as to affect only the reed 56 because that reed has been made predeterminedly of a length to establish a period of vibration therein agreeing with that frequency. Therefore, the closing of the circuit through 6| will energize the GM magnet and also the RM magnet connected in the return circuit thereof, resulting in the withdrawal of the RM pin 83 from its normal position in the orbit of the lug 68 and the moving of the pin 11 of the GM magnet into said orbit. However, the movement of the pin Tljust stated causes opening of the contacts 96, 9| thereby breaking the'circuit through, and deenergizing, the holding magnet 12. immediately releases the holding finger 86 from a notch of the holding disk 69 and permits the shaft 66 to again rotate the selector lug 68 until it comes in contact with the stop pin 11 in its path. .The stopping of the lug against the pin 11 will cause said lug to engage the spring contact associated with the binding post I6 and complete a circuit through the G (green) light.

The above operation to initiate the green light signal has been described as and when the train inductor 35 is in registry with the trackside inductor I. When these two inductors pass out of registry, as with the continued movement of the train in the direction of the arrow 48, then the frequency in the primary circuit of the transform-er 43 is changed to the normal frequency of the generator 39, inducing a corresponding change in frequencies passing through the mag-v nets 52, 53 etc. and the reed 56 will then stop vibrating since it is no more in resonance with the generator frequency. Cessation of vibration of this reed causes the contact 6| to remain open leaving the GM and RM magnets deenergized, the former causing retraction of its pin 11 from the orbit of the lug 68 with prior closing of contacts 96, 9| to reenergize the holding magnet 12 which results in the engagement of the holding finger 86 with the proper notch of the holding disk 69 to retain the lug 68 in contact to continue illumination of the G (green) light. Simultaneously with this is the release of the pin 83 from the RM magnet to move into its normal position in the orbit of the lug 68 when the latter is next released from the position just described. 1 The Y (yellow) lamp is lighted when the train inductor passes over the trackside inductor in substantially the same manner except that the control for the Y signal is through the magnet 29 of the trackside circuits and this will create a certain frequency in the trackside circuit corresponding to the R. PJM; of the shaft I6 in combination with the number of projections 26 on the control wheel 25. Obviously, the number of projections on the wheel 25 will be different from the number of projections on any of the other wheels on said shaft l6. The trackside frequency being established, current of a corresponding frequency will be induced in the train carried transformer circuits resulting in the passage of a current of a frequency through the magnets 52, 53, etc. such as to cause vibration of the reed 55, which has been predeterminedly tuned with resonance of that frequency by virtue of the clamp 59. Vibration of the reed 55 closes the contact 60 to cause energization of the YM and RM magnets, which respectively causes projection of the pin 88 into the orbit of the lug 68 and retraction of the pin 83 out of said orbit. However, immediately the pin 88 begins to move into said orbit, the contacts 93 and 95 are opened, thereby deenergizing the holding magnet 12 and releasing the holding finger 86, whereupon the lug 68 will be free to travel around in its orbit until it is stopped by the pin 88, and in this position said lug will be in engagement with the spring contact associated with the binding post 15 and thus close the circuit to and through the Y (yellow) lamp.

When the train inductor passes off the trackside inductor then the frequency of the second- This ary transformer circuit will be changed to that of the generator 39, thus causing cessation of the.

vibration of the reed 55, leaving the contact 68 open, and causing deenergization of YM and RM, the former causing first the closing of the contacts 93, 95 resulting in reenergization of the holding magnet 12 to move the holding finger 86 into a notch 18 to retain the lug 88 in engagement to close the circuit through the Y lamp, and second the retraction of pin 88 out of the orbit of the lug 68 while simultaneously causing the pin 83 of the RM magnet to move again into its normal position.

In the operation of the device to illuminate the R (red) lamp, magnet 58 of the roadside circuits must first be deenergized to open contact II. This is accomplished in any desired manner in accordance with traffic signal conditions, and when the contact II is so, opened, then the path of low reluctance through the trackside inductor is not interrupted by any of the choke coils 6, 1,

8 or 9. This results in the maximum flow of magnetic flux when the train inductor passes over the trackside inductor, and this in turn results in the voltage through coil 45 being increased to neutralize the voltage through coil 48, and thereby causes the current to drop to zero through the primary of the transformer. There is correspondingly no flow of current from the secondary of said transformer, resulting in deenergization of all frequency relays and magnets such as 5|, 52, and 53 etc. However, when magnet 5| is deenergized, contact I83 is open, breaking the circuit to and through the holding magnet 12 immediately releasing the holding finger 86 from its notch in the holding disk 53, and permitting the shaft 66 to rotate the lug 68 until it is stopped by the RM pin 83 which is normally in the orbit of said lug. When this occurs, said lug will engage the contact finger of post 14 and complete the circuit through the R lamp.

When the train inductor passes off the trackside inductor the normal voltage will be reestablished through the transformer 43, thereby causing voltage in the secondary of said transformer to reenergize magnet 5! which picks up its armature 54 and closes contact I 83. This results in the reenergization of the holding magnet 12 bringing the holding finger 86 into locking position with respect to the holding disk 69 to maintain, the lug 68 in engagement with the spring contact to continue the'illumination of the R lamp. The pin 83 is normally in the orbit of the lug 68 and is only moved therefrom when a frequency is transmitted by the trackside coils.

In connection with all the foregoing, it is, of

course, to be understood that this invention is ap-' plicable to a train system wherein the track is divided into the usual blocks, insulated from each other, each block having a trackside inductor located at a point which is called the control location and which is generally at or-slightly in advance of the entrance to the block. Each inductor is also connected .as indicated in the drawing to a relay such as It for controlling the circuit through the choke coils of the inductor, and the circuit in which said relay is located also includes contacts such as 23, 28 etc. which may be opened or closed individually by magnets operated in accordance with the traffic conditions. Each trackside inductor therefor is adapted, when the train inductor passes thereover, to impart to the latter a signal indicating trafiic conditions or to initiate automatically some operation which is important and necessary to the control of the train, the circuits for imparting such signal being controlled by the particular frequency established by mechanical means such as the wheels 20, 25 etc. Also it should be stated that the governor I] may be one so designed as to insure a predetermined and relative constant R. P. M. of the shaft I6. In other words, if the speed of the motor turns the shaft l6 too fast, said governor may operate a switch to open the circuit through the motor so that it will readily be understood that the R. P. M. of the shaft "5 may be varied to give one set of predetermined frequencies'through the various wheels 20, 25 etc. and then the governor may be adjusted whereby a maximum R. P. M. different from the first R. P. M. may be established as a result of which a different set of predetermined frequencies may be given the same wheels.

It is obvious that those skilled in the art may vary the details of construction as well as combinations of steps constituting the method without departing from the spirit of the invention, and therefore it is not desired to be limited to the foregoing except as may be required by the claims.

What is claimed is:

1. In a train signaling system the combination of trackside inductors and a train carried inductor the latter carrying a magnetic flux, the former offering a path of low reluctance to said flux; and means on the roadway for interrupting the flow of flux through the path of low reluctance at a predetermined frequency to produce a pulsating current in the train carried inductor of similar frequency.

2. In a train signaling system the combination of trackside inductors and a train carried inductor the latter carrying a magnetic flux, the former offering a path of low reluctance to said flux; and means on the roadway for selectively interrupting the flow of flux through the path of low reluctance at different predetermined frequencies to produce a plurality of pulsating currents in the train carried inductor of similar frequency. a

3. In a train signaling system the combination of trackside inductors and a train carried inductor the latter carrying a magnetic flux, the former offering a. path of low reluctance to said flux; means on the roadway for interrupting the flow of flux through the path of low reluctance at a predetermined frequency; and a train carried device responsive only to the predetermined frequency.

4. In a train signaling system the combination of trackside inductors and a train carried inductor the latter carrying a magnetic flux, the former offering apath of low reluctance to said flux; and means on the roadway for interrupting the flux flow through the path of low reluctance at a predetermined frequency adjustably in accordance with a predetermined trafiic condition, the modified flux producing a pulsating current in the train carried inductor -of similar frequency for signal control purposes.

5. Automatic train control apparatus comprising a train carried impulse coil a source of pulsating current inductively energizing said impulse coil through the medium of a magnetic flux; means including a trackside inductor for controlling the magnetic flux through said coil when passing a control location of the track, said trackside inductor including means to intermittently control the quantity of the magnetic flux through the impulse coil to establish therethr'ough a current of predetermined frequency; and a device on the train controlled by impulses from said'coil of similar frequency.

' 6. Automatic train control apparatus comprising a train carried inductor having a coil excited by a pulsating current as well as an impulse coil in inductive relation thereto, a trackside inductor with which the train carried inductor is inductively cooperable to receive a magnetic flux activated by said exciting coil, said trackside inductor having selectively controlled means to vary at predetermined frequencies said flux flow from said exciting coil through said impulse coil, and train control signal means controlled by impulses from said impulse coil. 7

7. Automatic train control apparatus comprising a train carried inductor having an exciting coil and an impulse coil in inductive relation with the exciting coil, said exciting coil energized from a train carried source of power to establish a magnetic flux through said coils, a trackside inductor with which the train carried inductor is inductively cooperable magnetically, said trackside inductor offering a path of low reluctance for the flow of said magnetic flux, traffic controlled choke coils on said trackside inductor to modify at a predetermined frequency the quantity of magnetic flux from the exciting coil through the impulse coil, and train control signal means controlled by impulses of similar frequency from said impulse coil.

8. Automatic train control apparatus comprising a train carried inductor having an exciting coil and an impulse coil in inductive relation with the exciting coil, said exciting coil energized from a train carried source of power to establish a magnetic flux through said coils, a trackside inductorwith which the train carried inductor is inductively cooperable magnetically, said trackside inductor offering a path of low reluctancefor the flow of said magnetic flux, trafiic controlled wayside means cooperating with said trackside inductor to modify at a predetermined frequency the quantity of magnetic flux from the exciting coil through the impulse coil, and train control signal means controlled by impulses of similar frequency from said impulse CO1 9. In a train signaling system the combination of trackside inductors and a train carried inductor the latter carrying a magnetic flux, the former offering a path of low reluctance to said flux when said inductors are in registry; and means on the roadway including said trackside inductor for establishing pulsations of a predetermined frequency in the current induced by said flux and flowing in the trackside inductor. said pulsations inductively modifying the magnetic flux to provide a corresponding pulsating current in the train carried inductor of similar frequency when said'inductors are in registry,

10.'In' a train signaling system the combination of a train carried inductor train supplied energy creating a flow of magnetic flux in said inductor; a trackside inductor offeringa path of low reluctance to said flux flow when the train inductor passes over the trackside inductor; and means on the roadway including said trackside inductor for modifying the flow of flux through the path of low reluctance at a predetermined frequency and consequently producing a modified reflected indication current in the train carried inductor for signal control purposes.

11. Automatic train control apparatus comprising a train carried impulse coil inductively activated by currentfrom a train carried source and establishing a magnetic flux, trackside equipment including a trackside inductor offering a path of low reluctance for said magnetic flux when said coil passes a control location of the track, said trackside inductor having choke coils for modifying the flow of magnetic flux in accordance with a predetermined frequency, said equipment further including means for selectively modifying the predetermined frequency of said 19 flux flow through the impulse coil, and. train control signal means controlled by impulses from said impulse coil having a similar frequency.

12. Automatic train control apparatus includtrain control signal means controlled by im- 10 pulses from said coil having a similar frequency.

HARRY W. RICHARDS. 

